How can we improve WCF Data Services?

add $format=json support in query URL

Now WCF data service supports getting json-formatted response by specifying Accept=application/json header in request only. However, It does not support $format=json as a query option, although it could be circumvented by copying code from http://code.msdn.microsoft.com/DataServicesJSONP and decorating service class with [JSONPSupportBehavior]. The lack of its support is a well-known issue. Hopefully it can be fixed soon and save people hassles of copying extra code and compiling and publishing.